Seattle heat

rick in Alaska

I just got in to Seattle to visit my son and am staying in his new townhouse apartment with him. He has informed me that he his having issues keeping his radiant heat consistent, and needs my help. I of course am ecstatic for a chance to troubleshoot this system.
So, he shows me around and I get to see all the individual wall mount fan convectors. I am now thinking, "why wall heaters with radiant?". So we finally get to the garage, which is just shy of absolutely useless to use or even to get in to, and he shows me the boiler system. Turns out it is a Rinnai on demand water heater. Not a boiler, just a water heater. It is tied in without a heat exchanger to a pump that runs continuously. The domestic is run through a mixing valve, as the water heater is set to run at 140 degrees.
So, after opening up an inspection panel, it has been determined that the pump goes to a distribution manifold with 7 pex lines leaving it, but no zone valves.
So, I have now determined that this system is set up so that the circulation pump runs continuously 24/7, which, since it is going through the water heater, is keeping the line at 140 degrees. Then when each individual room wants heat, the wall mounted high voltage thermostat turns the fan on to the heater. Since there is always hot water flowing through it, the heat blows out immediately, heating the space. I have also determined that it is not radiant heat, as advertised.
I was dumbfounded. This heater is constantly having to heat the water to have heat available to these heaters. All day, everyday! And the way they wired in the circulation pump, you can't shut it off without shutting off the water heater also.
Right now this is a somewhat tolerable, but barely, situation since heat is still somewhat needed. But, it is wearing out the water heater prematurely, is costing too much to run, all the convectors are warm all the time, and last but definitely not least, when it gets to be summertime, this place is going to get HOT!
Since this is a rental, we really can't do anything about it, but wanted input from others as to options to fix it.
I don't see any re-piping except at mechanical area. I am thinking at a bare minimum to install an inline switch to just be able to turn the pump off in the summertime. Seems to me that maybe if a central thermostat could be put in that the pump could be set up on a reset of some sorts to help at least get main temperature lower on low load days, and have ability to have wwsd.
Ok, ready for others input. (Except complete tear out, cause I don't see that happening).
Rick

icesailor

Sounds like another giant leap in the evolution of heating and potable hot water heating.

BobC

Might even be a contender for the Darwin Award!

Bob

Paul Pollets

This type of heating is common in newer Seattle townhomes and is installed because it is relatively inexpensive. Funny how it is marketed as "radiant heat".
It's expensive to fix and repair, most have used non-barrier tubing making repairs or replacement even more difficult (and pricey). It's hard to get it across to builders that this is not the way to go, low price trumps quality and efficiency. Especially when Seattle can afford the real deal.

hot_rod

That struck me as odd also, Paul. I recently traveled the Seattle area with our rep, PacWest. That area reeks of $$.

I remember a system like that connected to solar thermal, Myson perhaps? The system kicked on the pump would circulate thru the convectors. A fan switch powered the blower on. Suns out, heats on!

I think you are on to a simple improvement with a master t-stat. perhaps a wireless device, like this.

Or maybe the constant circulation is the "anti legionella" function

icesailor

The more money in the community, the more prevalent the Cheap Gene DNA is.

They mostly think that the quality price is trying to rip them off, and the low price is the smartest and best in the room.

Until it doesn't work and you can't find him to come back.

Paul Pollets

There are significant loopholes in the WA state codes (and city codes) that allow water heaters to be used as a heat source. Many of these systems have manual fills which exempts the RPZ and boiler permit. What you're left with is what you get. That each fan convector requires a 110v fan to operate + the fan noise = F on the comfort or efficiency scale. The new combi boilers or cabinet models (ie Viessmann 222F) offer better choices but builders or developers having a Cheap Attack seems to prevail.

rick in Alaska

I was kind of thinking about central wireless thermostats also. They could go back to the manifold where zone valves could be installed on each loop. Would not be cheap for sure, but I do not see much alternative without tearing in to the walls.
I just don't want my son to have to live with a system that is going to be costly to run, and where it is going to be overheating the place in the summer.
We need to convince the new owner of this place that it could be cost effective to fix it now. Since the pump is running full time and the water heater is keeping the line at 140, it is prematurely wearing out the heater. Not sure if that info can be digested by them or not, or if they will be interested in doing anything about it or not. Time will tell.
Rick

SWEI

As long as the tenants are paying the utility bills, there's just not much incentive for a bottom-line landlord to fix anything. IME.

We're proposing a different model down here for a couple of new multi-family projects. Landlord builds efficient, clean, green building and rents units with utilities included. Over the next 20 years, landlord gets to keep a nice chunk of the profits that would have gone to the utility under the conventional model. It's just another profit center.

tim smith

Ugggh, combo heat/ hot water heaters. We work on wayyyy too many of them. They are always haphazard systems. Definitely a brick short or 4 of a radiant system. They work kind of. They are mediocre at best. And yes, you have to replace the heating device every 10 yrs or so. So not much of a value.